1. Field of the Invention
The present invention relates to a planar heating element using carbon micro-fibers and a method for manufacturing the same, and more particularly to a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of realizing uniform temperature distribution of the entire heating element, preventing an increase in the temperature due to reduction of local resistance, prolonging a life of the heating element, and maintaining performance even when a local external load is exerted by forming a ground of the planar heating element using mixed carbon micro-fibers, pulp and synthetic fibers, and then coating carbon powder mixed with a conductive polymer on both surfaces of the ground.
2. Description of the Related Prior Art
Generally, a planar heating element made of carbon is used as a residential heating material since it is safe, makes no noises and eliminates the danger of an electromagnetic wave at the maximum.
Further, it may be used as a heating material in a commercial site such as an office or a business section. It may be used in industrial heating of a car, a warehouse, various tents and the like as various industrial heating devices. It may be used in plastic tents and the agricultural equipment such as agricultural product drying equipment. It may be used for removing snow and ice in the road, station, runway, and bridge. It may be used in portable warm-keeping equipage for relaxation and cold protection and health products, electric home appliances and livestock heating apparatuses.
In a conventional planar heating element, after carbon powder is mixed with a binder, the mixed carbon powder and binder are printed in a specified shape on a polyester (PET) film. Then, the carbon powder and binder are insulatingly adhered to the planar heating element using the polyester (PET) film and ethylene vinyl acetate (EVA) serving as a thermal adhesive.
However, the conventional planar heating element has a limited heating temperature. Theoretically, when a distance between both electrodes is 300˜500 mm, a heating temperature is about 83° C. Actually, the temperature and use of the conventional planar heating element are restricted and a material of an insulating film is limited. In the heating elements of a specified temperature (about 65° C.) or more, EVA of the insulating film swells, thereby causing defects on the appearance and performance of the planar heating element. Since a common temperature is equal to or smaller than 60° C. when a distance between both electrodes is 300˜500 mm, the conventional planar heating element is manufactured only as a limited planar heating element.
Further, the conventional planar heating element is sensitive to folding. That is, when the film is folded, a non-conducting state and fire may occur by an electricity concentration phenomenon along a folded interface.
Further, the conventional planar heating element employs only PET to form a regularly arranged pattern. An electric shock and defects may occur due to wrinkling in use. Various experiments have been conducted to prevent wrinkling. However, it is difficult to find an adhesive insulating material and a manufacturing method while maintaining a regularly arranged pattern.
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of allowing the heating element to be used at a high temperature and applied to various uses by using a carbon heating element having a complex structure to highly improve a temperature application range.
Further, it is another object of the present invention to provide a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of manufacturing heating elements of various temperatures by selectively using an insulating finishing material according to the heating temperature to form an insulating layer.
Further, it is yet another object of the present invention to provide a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of relatively prolonging a life of the heating element by preventing the carbon micro-fibers from being in contact with air, wherein an insulating layer is formed by using a T-die ejecting molding method instead of a conventional heating element or heat roller pressing laminating method or by heat-pressing molding, and particles of the carbon micro-fibers are mixed with an organic binder.
Further, it is yet another object of the present invention to provide a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of maximizing energy efficiency by punching the planar heating element using a flat plate press or a roll press for regular arrangement, and capable of increasing economical efficiency and safety by providing an insulating function and an waterproof function to a portion formed by cutting the planar heating element in its longitudinal direction.
Further, it is yet another object of the present invention to provide a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of forming heating elements having various functions for various uses by selecting an insulating material from a group consisting of PE, LDPE, LLDPE, PVC, tarpaulin, TPU, PU (polyurethane) and the like, which have ductility even in folding, and resin films such as epoxy impregnated fiberglass cloth (prepreg) and phenolic impregnated fiberglass cloth, which have high hardness to provide a mechanical strength to the insulating material.
Further, it is yet another object of the present invention to provide a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of manufacturing the planar heating element having multi-functions by allowing the heating element to have various widths (when a distance between both electrodes is 2400 mm, a heating temperature is about 35˜150° C.), a maximum heating temperature of 380° C. and various surface materials for an insulating layer, and capable of highly reducing unnecessary electricity consumption and achieving maximum power reduction by forming a heating portion in a specified pattern.
Further, it is yet another object of the present invention to provide a planar heating element using carbon micro-fibers and a method for manufacturing the same capable of allowing the heating element to continuously perform normal functions even in folding or under partial damage by manufacturing the planar heating element having a complex multi-layer structure, capable of preventing a short circuit to maintain a heating function by reducing power when the unit load is concentrated at one spot to generate the same electricity for the concentrated unit load, capable of preventing a crack in a heating portion and solving environmental problems by using 100% water-soluble adhesive, a diluting agent and water, and capable of prolonging a life of the heating element and improving long-term heat resistance by appropriately maintaining a volatile remaining amount.